﻿package com.example.android.BluetoothChat;


import java.io.IOException;
import java.util.List;

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

class Preview extends SurfaceView implements SurfaceHolder.Callback {
  SurfaceHolder mHolder;
  Camera mCamera;

  Preview(Context context) {
      super(context);

      // Install a SurfaceHolder.Callback so we get notified when the
      // underlying surface is created and destroyed.
      mHolder = getHolder();
      mHolder.addCallback(this);
      mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
      Log.i("cyy","preview constructing....");
  }

  public void surfaceCreated(SurfaceHolder holder) {
      // The Surface has been created, acquire the camera and tell it where
      // to draw.
      mCamera = Camera.open();
      try {
         mCamera.setPreviewDisplay(holder);
         Log.i("cyy","preview surfaceCreated....");
      } catch (IOException exception) {
          mCamera.release();
          mCamera = null;
          // TODO: add more exception handling logic here
      }
  }

  public void surfaceDestroyed(SurfaceHolder holder) {
      // Surface will be destroyed when we return, so stop the preview.
      // Because the CameraDevice object is not a shared resource, it's very
      // important to release it when the activity is paused.
      mCamera.stopPreview();
      mCamera.release();
      mCamera = null;
      Log.i("cyy","preview surfaceDestroyed....");
  }


  private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
      final double ASPECT_TOLERANCE = 0.05;
      double targetRatio = (double) w / h;
      if (sizes == null) return null;

      Size optimalSize = null;
      double minDiff = Double.MAX_VALUE;

      int targetHeight = h;

      // Try to find an size match aspect ratio and size
      for (Size size : sizes) {
          double ratio = (double) size.width / size.height;
          if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
          if (Math.abs(size.height - targetHeight) < minDiff) {
              optimalSize = size;
              minDiff = Math.abs(size.height - targetHeight);
          }
      }

      // Cannot find the one match the aspect ratio, ignore the requirement
      if (optimalSize == null) {
          minDiff = Double.MAX_VALUE;
          for (Size size : sizes) {
              if (Math.abs(size.height - targetHeight) < minDiff) {
                  optimalSize = size;
                  minDiff = Math.abs(size.height - targetHeight);
              }
          }
      }
      return optimalSize;
  }

  public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
      // Now that the size is known, set up the camera parameters and begin
      // the preview.
      Camera.Parameters parameters = mCamera.getParameters();

      List<Size> sizes = parameters.getSupportedPreviewSizes();
      Size optimalSize = getOptimalPreviewSize(sizes, w, h);
      parameters.setPreviewSize(optimalSize.width, optimalSize.height);

      mCamera.setParameters(parameters);
      mCamera.startPreview();
      Log.i("cyy","preview surfaceChanged....");
  }

}
